JP2018083944A - Rubber composition for tire tread and tire manufactured using the same - Google Patents

Abstract

A raw rubber containing natural rubber, solution-polymerized styrene-butadiene rubber and neodymium butadiene rubber, a reinforcing filler containing highly dispersible silica and carbon black, and an unsaturated fatty acid content of 60 to 90% by weight. A rubber composition for a tire tread containing natural oil, and a tire manufactured using the rubber composition. [Effect] By producing a tire using the rubber composition for a tire tread of the present invention, excellent braking performance, wear resistance performance and durability aging performance can be exhibited. [Selection figure] None

Description

  The present invention relates to a raw rubber containing natural rubber, solution-polymerized styrene-butadiene rubber and neodymium butadiene rubber, a reinforcing filler containing highly dispersible silica and carbon black, and an oleic acid content of 70 mol% or more. It is the technique regarding the rubber composition for tire treads containing the modified oil which is, and the tire manufactured using it.

  In recent years, as consumer interest and expertise in automobiles and tires has increased and products have diversified, the performance requirements for the automobile industry have increased. The main markets of the automobile industry are broadly divided into Europe and North America. The European market is mainly required for performance, mainly handling and braking performance, and stability and durability are important for the North American market. Be recognized.

  The European market has introduced a labeling system for tire performance since 2012, and provides consumers with information on braking performance on wet roads, low fuel consumption performance, and noise rating. Therefore, recently, the tire industry has developed new products mainly with performance indicated by labels. This clearly shows a trade-off tendency that if one performance is selected, the other performance becomes disadvantageous.

  Typical trade-off performance is wear resistance, which is an important factor in customer satisfaction with tire purchase costs, snow performance that affects winter snow and snow braking and handling performance, and long-term safety of tire operation. This corresponds to the fatigue resistance that determines the above.

  The tire industry is gradually growing into an all-season tire with the development of the North American market, from the environment that was divided into summer and winter in the existing European market. When referring to the trade-off performance of a typical four-season tire, in general, the braking performance on a wet road surface is a performance that conflicts with the wear performance and the braking performance on an icy and snowy road surface. The braking performance of wet road surface can be improved while increasing the content of silica with high styrene content and silica as a reinforcing agent, but this increases the hardness and modulus of rubber, so the braking performance of ice and snow road surface with low hardness Rather tend to lower.

  Also, in terms of the glass transition temperature (Tg) of rubber, the braking performance of wet roads is advantageous at high glass transition temperatures, but the wear performance and braking performance of icy and snowy roads are advantageous at lower flexible glass transition temperatures. It is.

  A general tire operating temperature range is -20 ° C to 40 ° C, and its temperature range is wide. However, this is because the synthetic oil used to facilitate the processing of rubber can elute from the inside of the tread during long-term running with high-temperature asphalt that rises to 40 ° C in midsummer, and finally the elastic property of rubber It changes the property and is recognized as a risk factor in the running stability of the tire. In particular, in a tire having a filler content of 100 phr or more, a large amount of synthetic oil must be used in order to ensure rubber mixing stability, which may contribute to long-term durability and aging characteristics of the tire. It has a bad effect.

Japanese Published Patent Publication No. 2001-253973 Korea Registration Gazette No. 0964308 Korean Registered Publication No. 1278216 Korean Published Patent Publication No. 2010-0120144

  An object of the present invention is to provide a rubber composition for a tire tread that maintains braking performance on a wet road surface and is excellent in wear resistance, ice / snow braking, and durable aging performance of a tread at a high temperature.

  Another object of the present invention is to provide a tire manufactured using the rubber composition for a tire tread.

  In order to solve the above-mentioned object, according to one embodiment of the present invention, the ratio of raw rubber 100 parts by weight, reinforcing filler 70-120 parts by weight, and linoleic acid: oleic acid ratio is 1: 0.5-1 The rubber composition for tire treads which contains 10-60 weight part of natural oil which is: 5 can be provided.

  The raw rubber may include 5 to 10 parts by weight of natural rubber, 40 to 70 parts by weight of solution-polymerized styrene-butadiene rubber, and 20 to 50 parts by weight of neodymium butadiene rubber.

  The solution-polymerized styrene-butadiene rubber has a styrene content of 20 to 50% by weight, a vinyl content of 10 to 40% by weight, a Tg of −50 to −20 ° C., and 20 to 40 parts by weight of SRAE oil. Can do.

  The neodymium butadiene rubber may have a cis-1,4-butadiene content of 95% by weight or more and a Tg of −100 to −120 ° C.

  The reinforcing filler may include 65 to 100 parts by weight of highly dispersible silica and 5 to 20 parts by weight of carbon black.

The highly dispersible silica may have a nitrogen adsorption value of 160 to 180 m ² / g and a CTAB adsorption value of 150 to 170 m ² / g.

  The natural oil is linoleic acid and oleic acid from any one natural oil selected from the group consisting of soybean oil, sunflower oil, cottonseed oil, corn oil, canola oil, palm oil, grape seed oil, and mixtures thereof. It may contain a mixture after extraction and separation.

  The natural oil may have a content of unsaturated fatty acids including linoleic acid and oleic acid of 60 to 90% by weight.

  The tire tread rubber composition is any one selected from the group consisting of bis- (trialkoxysilylpropyl) polysulfide (TESPD), bis-3-triethoxysilylpropyl tetrasulfide (TESPT), and mixtures thereof. One silane coupling agent may be further included in an amount of 5 to 20 parts by weight with respect to 100 parts by weight of the raw rubber.

  According to another preferred embodiment of the present invention, a tire manufactured using the rubber composition for a tire tread can be provided.

  When the rubber composition for a tire tread according to the present invention is used, a tire excellent in braking performance, wear resistance performance and durability aging performance can be produced.

  Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example for more specifically explaining the technical idea of the present invention, and is not intended to limit the technical idea of the claimed invention. It is only defined by the scope of the claims of the invention.

  The present invention provides a rubber composition for a tire tread that maintains braking performance on a wet road surface and is excellent in wear resistance, ice / snow braking, and durable aging performance of a tread at a high temperature. -100 parts by weight of raw rubber comprising butadiene rubber and neodymium butadiene rubber; 70-120 parts by weight of reinforcing filler comprising highly dispersible silica and carbon black; and the ratio of linoleic acid: oleic acid is 1: 0.5-1 : 5 and a rubber composition for tire treads containing 10 to 60 parts by weight of a natural oil having an unsaturated fatty acid content of 60 to 90% by weight.

  Hereinafter, each component will be described in detail.

  1) Raw rubber

  The raw rubber may include 5 to 10 parts by weight of natural rubber, 40 to 70 parts by weight of solution-polymerized styrene-butadiene rubber, and 20 to 50 parts by weight of neodymium butadiene rubber.

  The natural rubber is a general term for rubber obtained from nature, and any natural rubber can be used, and the place of origin is not limited. The natural rubber can be described as polyisoprene by chemical name, and more preferably can contain cis-1,4-polyisoprene as a main component.

  The natural rubber may be included in an amount of 5 to 10 parts by weight with respect to 100 parts by weight of the raw rubber. When the natural rubber is contained in an amount of less than 5 parts by weight, the natural characteristics of the natural rubber having a crystallized structure are slight, and when it exceeds 10 parts by weight, it is disadvantageous in terms of compatibility with the synthetic rubber. May occur.

  The solution-polymerized styrene butadiene rubber (Styrene-Butadiene Rubber, SBR) has a styrene content of 20 to 50% by weight, a vinyl content of 10 to 40% by weight, and a glass transition temperature (Tg) of −50 ° C. to −20 ° C. It is. If the styrene content, vinyl content, and glass transition temperature are out of the above ranges, the braking performance on the wet road surface may be adversely affected.

  The solution-polymerized styrene butadiene rubber can increase the glass transition temperature and improve the grip performance.

  The solution-polymerized styrene butadiene rubber may include 20 to 40 parts by weight of aromatic oil per 100 parts by weight of the raw rubber elastic body. Preferably, the aromatic oil may include 20 to 40 parts by weight of SRAE (Safety Residual Aromatic Extract) oil, and such SRAE oil is a styrene butadiene rubber (SBR) reduced by the influence of styrene. The flexibility can be increased. More preferably, when considering the remarkable effect of improving the flexibility of SBR, it is preferable to contain 35 to 40 parts by weight of SRAE oil. When the SRAE oil is less than 20 parts by weight or more than 40 parts by weight, the effect of improving the braking performance on an icy and snowy road surface or a wet road surface may be poor.

  At this time, the SRAE oil is an oil obtained by re-extracting TDAE (Treated Distillate aromatic extract) oil extraction residue, which is benzo (a) pyrene (Benzo (a) pyrene), benzo (e) pyrene (Benzo (e) pyrene), benzo (a) anthracene (Benzo (a) anthracene), benzoanthracene (Chrysene), benzo (b) fluoranthene, benzo (j) fluoranthene (Benzo (j) fluoranthene), benzo (k) fluoranthene (Benzo (k) fluoranthene), and dibenzo (a, h) anthracene (Dive) The total content of PAH (polycyclic aromatic hydrocarbon) components including zo (a, h) anthracene) is 3% by weight or less, which is the same as TDAE oil, but the kinematic viscosity is 95 SUS (Saybolt second on the basis of 210 ° F.) or more And can be distinguished from TDAE oil. In addition, the SRAE oil may be an oil having a characteristic that the aromatic component in the softener is 15 to 25% by weight, the naphthenic component is 35 to 55% by weight, and the paraffinic component is 25 to 45% by weight. .

  The solution polymerized styrene butadiene rubber may be contained in an amount of 40 to 70 parts by weight with respect to 100 parts by weight of the total raw rubber.

  The solution-polymerized styrene butadiene rubber has a wide molecular weight distribution, is excellent in processability, and has a high molecular weight, and is advantageous in wear resistance. More preferably, the weight average molecular weight (Mw) of the solution polymerized styrene butadiene rubber may be 1,200,000 to 1,700,000 g / mol, and the molecular weight distribution is 1.5 or more, more preferably 1. It may be 5 to 3.0, more preferably 1.5 to 2.5. In the case of the raw rubber used, since the styrene and vinyl contents are at a low level, the glass transition temperature is also low, so that the braking performance on ice and snow road surfaces is also advantageous.

The neodymium butadiene rubber refers to butadiene rubber polymerized using a neodymium catalyst, and the neodymium catalyst refers to neodymium carboxylate (Nd (OOCR) ₃ (where R is a generic name for alkyl groups)). A compound containing a ligand around the neodymium metal may be effective.

  The neodymium butadiene rubber may be a high cis neodymium butadiene rubber having a cis-1,4-butadiene content in the molecule of 95% by weight or more. By using butadiene rubber having a high cis bond content in this way, the wear resistance and braking characteristics of the tire rubber composition can be improved.

  The neodymium butadiene rubber may have a glass transition temperature (Tg) of -100 ° C to -120 ° C, a molecular weight distribution of 1.5 to 2.5, and no oil.

  The neodymium butadiene rubber has a narrow molecular weight distribution and a linear molecular structure compared to cobalt butadiene rubber or nickel butadiene rubber, and is advantageous in rotational resistance due to low hysteresis heat loss. Moreover, since the neodymium butadiene rubber has the lowest glass transition temperature among the raw rubber compositions, the braking performance on ice and snow road surfaces is also advantageous.

  The neodymium butadiene rubber may be included in an amount of 20 to 50 parts by weight with respect to 100 parts by weight of the total raw rubber. When the neodymium butadiene rubber is included in an amount of less than 20 parts by weight, the wear resistance performance and the low fuel consumption performance are disadvantageous. When the amount exceeds 50 parts by weight, the workability may be reduced.

  In addition to the natural rubber, solution polymerized styrene butadiene rubber and neodymium butadiene rubber, the raw rubber of the present invention is deformed with polybutadiene rubber, conjugated diene aromatic vinyl copolymer, hydrogenated natural rubber, olefin rubber, and maleic acid. Any selected from the group consisting of prepared ethylene-propylene rubber, butyl rubber, copolymer of isobutylene and aromatic vinyl or diene monomer, acrylic rubber, rubber containing ionomer, halogenated rubber, chloroprene rubber, and mixtures thereof Or one of them.

  2) Reinforcing filler

  Meanwhile, the tire tread rubber composition may include high dispersibility silica and carbon black as reinforcing fillers.

  The rubber composition for tire treads according to one embodiment of the present invention includes a highly dispersible silica having particles smaller than general silica (Intermediate Dispersibility Silica). Therefore, the rubber composition for tire treads has high dispersibility. As the wear resistance increases, braking performance and low rotational resistance can be improved.

The highly dispersible silica may have a nitrogen adsorption value of 160 to 180 m ² / g, a CTAB adsorption value of 150 to 170 m ² / g, and a DBP oil absorption of 180 to 200 cc / 100 g. The highly dispersible silica may be contained in an amount of 65 to 100 parts by weight with respect to 100 parts by weight of the raw rubber. When the silica is contained in an amount of less than 65 parts by weight, the braking performance is lowered, and when it exceeds 100 parts by weight, there may be a problem that the wear resistance performance and the low fuel consumption performance are disadvantageous.

The carbon black may have a nitrogen adsorption surface area (N2SA) of 30 to 300 m ² / g and a DBP (n-dibutyl phthalate) oil absorption of 60 to 180 cc / 100 g. However, the present invention is not limited to this.

When the nitrogen adsorption specific surface area of the carbon black exceeds 300 m ² / g, the processability of the tire rubber composition may be disadvantageous, and when it is less than 30 m ² / g, the carbon black as a filler is reinforced. Performance may be disadvantageous. Further, if the DBP oil absorption amount of the carbon black exceeds 180 cc / 100 g, the processability of the rubber composition may be lowered, and if it is less than 60 cc / 100 g, the reinforcing performance by the carbon black as the filler is disadvantageous. May be.

  Representative examples of the carbon black include N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539. N550, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 or N991.

  The tire tread rubber composition according to an embodiment of the present invention may include 5 to 20 parts by weight of the carbon black and less than 5 parts by weight of the carbon black with respect to 100 parts by weight of the raw rubber. In some cases, the effect of the reinforcing property is slight. When the amount exceeds 20 parts by weight, the braking performance on the icy and snowy road surface may decrease due to a decrease in rotational resistance and an excessive increase in reinforcing property.

  Usually, in rubber compositions, silica can be chemically bonded to the rubber while being modified to be organophilic within the rubber through reaction with a silane coupling agent. Thus, when the surface chemical properties of the silica are deformed, the movement of the silica within the rubber is limited and the hysteresis is lowered, resulting in a decrease in heat generation and rotational resistance of the rubber composition. However, if the silica is not sufficiently dispersed in the rubber, the reduction in heat generation and rotational resistance is slight, and rather the wear resistance may be lowered. Therefore, the tire tread according to one embodiment of the present invention. The rubber composition may further contain a silane coupling agent.

  The silane coupling agent is not particularly limited as long as it is used as a coupling agent for silica in a normal rubber composition. Specifically, from sulfide silane compounds, mercapto silane compounds, vinyl silane compounds, amino silane compounds, glycidoxy silane compounds, nitro silane compounds, chloro silane compounds, methacrylic silane compounds, and mixtures thereof. It may be selected from the group consisting of:

  The sulfide-based silane compounds include bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (4-triethoxysilylbutyl) tetrasulfide, and bis (3-trimethoxysilyl). Propyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (4-trimethoxysilylbutyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (2-triethoxysilylethyl) Trisulfide, bis (4-triethoxysilylbutyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (2-trimethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) tris Fido, bis (3-triethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (4-triethoxysilylbutyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (2- Trimethoxysilylethyl) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylene Any selected from the group consisting of benzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, 3-triethoxysilylpropyl methacrylate monosulfide, and mixtures thereof It may be one.

  The mercapto-based silane compound is selected from the group consisting of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and combinations thereof. Any one may be sufficient. The vinyl silane compound may be any one selected from the group consisting of ethoxysilane, vinyltrimethoxysilane, and combinations thereof.

  The amino silane compound includes 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxysilane, and 3- (2-aminoethyl) aminopropyltrimethoxysilane. And any one selected from the group consisting of combinations thereof.

  The glycidoxy-based silane compound includes γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and these Any one selected from the group consisting of these may be used. The nitro silane compound may be any one selected from the group consisting of 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, and combinations thereof. The chlorosilane compound is selected from the group consisting of 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, and combinations thereof. Any one may be sufficient.

  The methacrylic silane compound may be any one selected from the group consisting of γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyldimethylmethoxysilane, and combinations thereof. There may be.

  Among the silane coupling agents, a sulfide-based silane compound is preferable in consideration of the coupling effect on silica, preferably bis- (trialkoxysilylpropyl) polysulfide (TESPD), bis-3-triethoxysilylpropyl. It may be any one selected from the group consisting of tetrasulfide (TESPT) and a mixture thereof.

  The silane coupling agent may be included in an amount of 5 to 20 parts by weight with respect to 100 parts by weight of the raw rubber. If the content of the silane coupling agent is less than 5 parts by weight, the dispersibility of the silica may be deteriorated because the conversion effect of the surface chemical characteristics with respect to the silica is slight. As a result, the reinforcing property and durability of the tire are reduced. May decrease. In addition, when the content of the silane coupling agent exceeds 20 parts by weight, the use of an excessive amount of the silane coupling agent may rather decrease the wear resistance and fuel efficiency of the tire. In consideration of the remarkable improvement effect, the silane coupling agent is more preferably contained in 5 to 7 parts by weight with respect to 100 parts by weight of the raw rubber.

  According to a more preferred embodiment of the present invention, carbon black may be used alone or a silane coupling agent may be further added alone, but more preferably, 50% by weight of TESPD or TESPT It is more effective to reinforce the reinforcing property of the filler and the effect of the highly dispersible silica by containing 5 to 20 parts by weight of the mixture obtained by mixing 50% by weight of carbon black with respect to 100 parts by weight of the raw rubber. .

  The tire tread rubber composition according to an embodiment of the present invention may further include a processing aid for enhancing the dispersibility of silica. Usually, the silane coupling agent plays a role of crosslinking to link the silanol group on the silica surface and the raw rubber of the composition, and serves to eliminate the strong cohesive force between silica and silica when used alone. . However, when the silica content in the rubber component or the specific surface area of the silica increases, the dispersibility often decreases despite the addition of the silane coupling agent.

  Therefore, in one embodiment of the present invention, an aliphatic compound, specifically a fatty acid ester compound, more specifically a fatty acid ester having 13 to 22 carbon atoms, is used as a processing aid in the rubber composition for a tire tread. By further including a metal salt modified with a system compound, the dispersibility of the silica contained in a high content can be improved, and the scorch stability, durability, and wear resistance can be improved.

  The processing aid is an amphiphilic substance containing both a hydrophilic group of a metal ion and a hydrophobic group of a fatty acid, and the metal ion reacts with a silanol group on the silica surface to react with a hydrogen bond or a dipole bond. In contrast to silica agglomerates that are strongly bonded to each other, de-agglomerate is induced during the mixing process by reducing intermolecular surface energy, resulting in a tire tread rubber composition Decrease the viscosity of the product to increase the flow property and improve the scorch stability, durability and wear resistance. In addition, the hydrocarbon group of the fatty acid serves as a plasticizer for improving processability by diluting the rubber chain with excellent compatibility with the rubber chain.

  Specifically, in the processing aid, the metal salt may be zinc soap, sodium soap, potassium soap, or zinc potassium soap. . However, since the sodium soap and potassium soap have a strong polarity, there is a possibility that the scorch stability and the vulcanization time may be shortened by reacting with silica before the silica and the coupling agent react. Accordingly, zinc soap is more preferable as the metal salt.

  Moreover, it is preferable that the said zinc soap contains 1-5 weight% of zinc components with respect to the total weight of a zinc soap. When the zinc content in the zinc soap is less than 1% by weight, the dispersion effect is insufficient, and when the zinc content exceeds 5% by weight, the formation of zinc salt increases, and the performance of the rubber composition decreases. There is a risk.

  The fatty acid ester may specifically be an ester of a saturated or unsaturated fatty acid having 12 to 22 carbon atoms, and more specifically may be an aliphatic or aromatic carboxylic acid.

  The modification of the fatty acid ester with respect to the zinc soap may be performed by mixing the fatty acid ester in a weight ratio of 20:80 to 40:60 and then performing a condensation reaction. At this time, the zinc soap in the processing aid is used. When the mixing weight ratio of the carboxylic acid and the fatty acid ester is out of the range of 20:80 to 40:60, the dispersibility improving effect may be lowered.

  The processing aid as described above is preferably contained in an amount of 0.5 to 5 parts by weight with respect to 100 parts by weight of the raw rubber. When the content of the processing aid is less than 0.5 parts by weight, the effect of dispersing the silica is insufficient, and when the content of the processing aid exceeds 5 parts by weight, the effect is greater than the amount of processing aid used. The degree of improvement is extremely small. In view of the remarkable improvement effect, the processing aid is more preferably contained in an amount of 1 to 3 parts by weight with respect to 100 parts by weight of the raw rubber.

  3) Natural oil

  The natural oil may include any one natural oil selected from the group consisting of soybean oil, sunflower oil, cottonseed oil, corn oil, canola oil, palm oil, grape seed oil, and mixtures thereof, and more preferably May include those obtained by extracting and separating unsaturated fatty acids from the natural oil and adjusting their contents. More preferably, linoleic acid and oleic acid are extracted from the natural oil, separated, mixed, and adjusted to an appropriate linoleic acid: oleic acid ratio. As the method for extracting, separating and mixing the unsaturated fatty acid, particularly linoleic acid and oleic acid as described above, any method can be used as long as it is a commonly used extraction and separation method of unsaturated fatty acid, preferably organic. Extraction using a solvent, supercritical fluid or the like, fractional crystallization, fractional distillation, or the like can also be used.

  The natural oil used in one embodiment of the present invention is an oil containing an unsaturated fatty acid content of 60 to 90% by weight, more preferably 70 to 90% by weight. When the content of the unsaturated fatty acid in the natural oil is less than 60% by weight or more than 90% by weight, the effect of improving the tire performance may not appear as much as desired physical properties.

  In this study, the ratio of oleic acid (OA) to linoleic acid (LA) in the unsaturated fatty acid (OA / OA) for the purpose of improving tire wear resistance, ice / snow braking and durability aging performance. LA) of 0.5 to 5, that is, linoleic acid: oleic acid of 1: 0.5 to 1: 5 can be used. More preferably, the linoleic acid: oleic acid ratio is 1: 1 to 1: 4, more preferably 1: 2 to 1: 3. When the ratio is less than 0.5, braking performance and wear resistance performance on icy and snowy road surfaces are excellent, but the trade-off between braking performance and rotational resistance on wet road surfaces is large, and on the contrary, when the ratio is 5 or more, wet Although there is a slight trade-off between braking performance and rotational resistance on the road surface, braking performance and wear resistance performance on icy and snowy road surfaces may also have a slight effect.

  More preferably, the natural oil may be used in an amount of 10 to 60 parts by weight with respect to 100 parts by weight of the raw rubber. When the natural oil is contained in less than 10 parts by weight, there may be a problem that the effect of wear performance and braking performance on snowy and snowy road surfaces is slight. There may be a problem that the braking performance on the road surface is excessively lowered.

  4) Other additives

  In addition to the above components, the rubber composition for a tire tread according to the present invention is selectively added with a vulcanizing agent, a vulcanization accelerator, a vulcanization acceleration aid, an antiaging agent, a softening agent, an adhesive, and the like. An agent can be further included singly or in combination of two or more.

  Any vulcanizing agent can be used as long as it can be contained in the rubber composition for tires, but metals such as sulfur-based vulcanizing agents, organic peroxides, resin vulcanizing agents, and magnesium oxide can be used. Oxides can be used.

  Examples of the sulfur vulcanizing agent include inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), colloidal sulfur, or tetramethylthiuram disulfide (TMTD). Organic vulcanizing agents such as tetraethylthiuram disulfide (TETD), dithiodimorpholine, and other vulcanizing agents that produce elemental sulfur or sulfur, such as amine disulfide. ), Polymeric sulfur and the like can also be used.

  Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di (t- Butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 1,3-bis (t-butylperoxypropyl) benzene, di-t-butylperoxy-diisopropylbenzene, t-butylperoxy Benzene, 2,4-dichlorobenzoyl peroxide, 1,1-dibutylperoxy-3,3,5-trimethylsiloxane, or n-butyl-4,4-di-t-butylperoxyvalerate can be used. .

  More preferably, a sulfur vulcanizing agent can be used as the vulcanizing agent. Examples of sulfur vulcanizing agents can be selected from elemental sulfur or vulcanizing agents that produce sulfur, wherein the vulcanizing agents that produce sulfur include amine disulfides, polymeric sulfur, and mixtures thereof. Any one selected from the group may be used. More preferably, according to one embodiment of the present invention, elemental sulfur can be used as the vulcanizing agent. The vulcanizing agent is contained in an amount of 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the raw rubber. As an appropriate vulcanization effect, the raw rubber is not very sensitive to heat and is chemically stable. It is preferable in that

  The vulcanization accelerator means an accelerator that accelerates the vulcanization speed or accelerates the retarding action in the initial vulcanization stage. Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, xanthate, and combinations thereof. Any one selected from the group can be used.

  Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), N, Selected from the group consisting of N-dicyclohexyl-2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N, N-diisopropyl-2-benzothiazolesulfenamide, and combinations thereof Any one of the sulfenamide compounds can be used.

  Examples of the thiazole vulcanization accelerator include 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), sodium salt of 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, and 2-mercapto. Benzothiazole copper salt, 2-mercaptobenzothiazole cyclohexylamine salt, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole, and these Any one thiazole compound selected from the group consisting of combinations can be used.

  Examples of the thiuram vulcanization accelerator include tetramethyl thiuram disulfide (TMTD), tetraethyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram disulfide, dipentamethylene thiuram monosulfide, dipentamethylene thiuram tetrasulfide, Any one thiuram compound selected from the group consisting of dipentamethylene thiuram hexasulfide, tetrabutyl thiuram disulfide, pentamethylene thiuram tetrasulfide, and combinations thereof can be used.

  Examples of the thiourea vulcanization accelerator include any one thiourea compound selected from the group consisting of thiocarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea, and combinations thereof. Can be used.

  Examples of the guanidine vulcanization accelerator include any one guanidine compound selected from the group consisting of diphenyl guanidine, diorthotolyl guanidine, triphenyl guanidine, orthotolyl biguanide, diphenyl guanidine phthalate, and combinations thereof. Can be used.

  Examples of the dithiocarbamate vulcanization accelerator include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate. , Zinc dipropyldithiocarbamate, zinc pentamethylenedithiocarbamate and piperidine complex, zinc hexadecylisopropyldithiocarbamate, zinc octadecylisopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, pentamethylenedithiocarbamate piperidine, dimethyldithiocarbamate Selenium, Ternidiethyldithiocarbamate Arm, diamyl dithiocarbamate cadmium, and any one of the dithiocarbamic acid-based compound selected from the group consisting of these can be used.

  Examples of the aldehyde-amine-based or aldehyde-ammonia-based vulcanization accelerator include acetaldehyde-aniline reactant, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant, and combinations thereof. The selected aldehyde-amine or aldehyde-ammonia compound can be used.

  As the imidazoline vulcanization accelerator, for example, an imidazoline compound such as 2-mercaptoimidazoline can be used. As the xanthate vulcanization accelerator, for example, a xanthate compound such as zinc dibutylxanthate is used. Can be used.

  More preferably, the vulcanization accelerator is an amine, disulfide, guanidine, thiourea, thiazole, thiuram, sulfenamide, and Inclusion of 1.0 to 2.5 parts by weight of any one compound selected from the group consisting of these mixtures with respect to 100 parts by weight of the raw rubber increases the productivity by promoting the vulcanization rate and This is preferable for maximizing the enhancement of rubber properties.

  The vulcanization accelerating agent is a compounding agent used in combination with the vulcanization accelerating agent to complete its accelerating effect. Any one selected from the group consisting of, and combinations thereof can be used.

  The inorganic vulcanization accelerator is selected from the group consisting of zinc oxide (ZnO), zinc carbonate, magnesium oxide (MgO), lead oxide, potassium hydroxide, and combinations thereof. Can be used. Examples of the organic vulcanization accelerator include stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutylammonium oleic acid, derivatives thereof, and combinations thereof. Any one selected from the group can be used.

  In particular, both the zinc oxide and the stearic acid can be used as the vulcanization accelerator, and in this case, the zinc oxide is dissolved in the stearic acid to form an effective complex (complex). ) To create advantageous sulfur during the vulcanization reaction, which can facilitate the rubber crosslinking reaction. When both the zinc oxide and stearic acid are used, it is preferable to use 1 to 10 parts by weight with respect to 100 parts by weight of the raw rubber for the role as an appropriate vulcanization accelerator.

  The anti-aging agent is an additive used for stopping a chain reaction in which a tire auto-oxidizes with oxygen. In addition to the anti-aging effect, the anti-aging agent must have high rubber solubility, low volatility, be inert to the rubber, and must not inhibit vulcanization. As the antioxidant, any one selected from the group consisting of amines, phenols, quinolines, imidazoles, carbamic acid metal salts, waxes, and combinations thereof should be selected and used. Can do.

  Examples of the amine antioxidant include N-phenyl-N ′-(1,3-dimethyl) -p-phenylenediamine, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, N, N′-diaryl-p-phenylenediamine, N-phenyl-N′-cyclohexyl-p-phenylene Any one selected from the group consisting of diamine, N-phenyl-N′-octyl-p-phenylenediamine, and combinations thereof can be used.

  Examples of the phenol-based anti-aging agent include phenol-based 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 2,2′-isobutylidene-bis (4,6-dimethylphenol), Any one selected from the group consisting of 2,6-di-t-butyl-p-cresol and combinations thereof can be used.

  As the quinoline antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline and its derivatives can be used. Specifically, 6-ethoxy-2,2,4-trimethyl- From 1,2-dihydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline, and combinations thereof Any one selected from the group can be used.

  As the wax, waxy hydrocarbon can be preferably used.

  Preferably, the antioxidant is N- (1,3-dimethylbutyl) -N-phenyl-p-phenylenediamine (6PPD), N-phenyl-n-isopropyl-p-phenylenediamine (3PPD), poly ( 1 to 5 parts by weight of any one compound selected from the group consisting of 2,2,4-trimethyl-1,2-dihydroquinoline (RD) and a mixture thereof with respect to 100 parts by weight of the raw rubber The inclusion is preferable in terms of anti-aging action and rubber solubility.

  The softening agent is added to the rubber composition in order to impart plasticity to the rubber to facilitate processing, or to reduce the hardness of the vulcanized rubber, and is used during rubber compounding or rubber production. Process oils. As the softening agent, any one selected from the group consisting of petroleum oils, vegetable oils and fats, and combinations thereof can be used, but the present invention is not limited thereto.

  As the petroleum oil, any one selected from the group consisting of paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof can be used.

  As typical examples of the paraffinic oil, P-1, P-2, P-3, P-4, P-5, P-6, etc. of Misho Oil Co., Ltd. can be mentioned. As representative examples, N-1, N-2, N-3, etc. of Misa Oil Co., Ltd. can be mentioned. As a representative example of the aromatic oil, A -2, A-3, and the like. `

  However, in recent years, when the content of polycyclic aromatic hydrocarbons (hereinafter referred to as “PAHs”) contained in the aromatic oil is 3% by weight or more due to increasing environmental consciousness, It is known that there is a high possibility of induction, and it is preferable to use TDAE (treated distributed aromatic extract) oil, MES (mild extraction sorbate) oil, RAE (residual aromatic extract) oil, or heavy naphthenic oil. it can.

  In particular, the oil used as the softener has a total content of PAHs components as defined above of 3% by weight or less and a kinematic viscosity of 95 ° C. or higher (210 ° F. SUS) with respect to the whole oil. A TDAE oil containing 15 to 25% by weight of aromatic components, 27 to 37% by weight of naphthenic components, and 38 to 58% by weight of paraffinic components can be preferably used.

  The TDAE oil has advantageous characteristics against environmental factors such as the possibility of inducing cancer of PAHs while improving the low temperature characteristics and fuel efficiency of the tire tread.

  Examples of the vegetable oil include castor oil, cottonseed oil, linseed oil, canola oil, soybean oil, palm oil, palm oil, peanut oil, pine oil, pineapple oil, corn oil, corn oil, safflower oil, sesame oil, olive oil. Any one selected from the group consisting of sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, safflower oil, tung oil, and combinations thereof can be used.

  The softener is preferably used in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the raw rubber in terms of improving the processability of the raw rubber.

  The pressure-sensitive adhesive further improves the tack performance between rubber and rubber, and improves the mixability, dispersibility and processability of other additives such as fillers, and contributes to the improvement of rubber physical properties. To do.

  Examples of the adhesive include a natural resin adhesive such as a rosin resin or a terpene resin, and a synthetic resin adhesive such as a petroleum resin, coal tar, or an alkylphenol resin. Can be used.

  The rosin resin may be any one selected from the group consisting of rosin resins, rosin ester resins, hydrogenated rosin ester resins, derivatives thereof, and combinations thereof. The terpene resin may be any one selected from the group consisting of terpene resins, terpene phenol resins, and combinations thereof.

  The petroleum resins include aliphatic resins, acid-modified aliphatic resins, alicyclic resins, hydrogenated alicyclic resins, aromatic (C9) resins, hydrogenated aromatic resins, C5-C9. Any one selected from the group consisting of copolymer resins, styrene resins, styrene copolymer resins, and combinations thereof may be used.

  The coal tar may be a coumarone-indene resin.

  The alkylphenol resin may be a p-tert-alkylphenol formaldehyde resin, and the p-tert-alkylphenol formaldehyde resin may be p-tert-butyl-phenolformaldehyde resin, p-tert-octyl-phenolformaldehyde, and these Any one selected from the group consisting of combinations may be used.

  The pressure-sensitive adhesive may be included in an amount of 0.5 to 10 parts by weight with respect to 100 parts by weight of the raw rubber. If the content of the pressure-sensitive adhesive is less than 0.5 parts by weight with respect to 100 parts by weight of the raw rubber, the adhesion performance is lowered, and if it exceeds 10 parts by weight, the physical properties of the rubber may be lowered. .

  The rubber composition for a tire tread can be produced by mixing the above components by a usual method. Specifically, typically during the first stage of thermomechanical processing or kneading at a maximum temperature reaching 110-190 ° C., preferably 130-180 ° C., and the finishing stage in which the cross-linking system is mixed Although it can manufacture by the continuous process of 2 steps | paragraphs including the 2nd step | paragraph which carries out mechanical processing at the low temperature of less than 110 degreeC, for example, 40-100 degreeC, this invention is not limited to this.

  The rubber composition for tire treads manufactured by the method as described above is a particulate carbon having physical properties optimized in consideration of the effect of improving the dispersibility of silica together with silica as a reinforcing filler. Oleic acid over linoleic acid (LA) in unsaturated fatty acids for the purpose of improving tire wear resistance, snow and snow braking and durability aging performance, including composites containing black and particulate silane coupling agents (Oleic acid, OA) ratio (OA / LA) is further added with natural oil limited to 0.5-5, while maintaining fuel efficiency, wear resistance, braking ability, life characteristics and cut tip The performance can be improved, and the appearance characteristics of the tire including the degree of coloring can be improved. Thereby, the rubber composition for a tire tread is not limited to a tread (tread cap and tread base), and may be included in various rubber components constituting the tire. Examples of the rubber component include a sidewall, a sidewall insert, an apex, a chafer, a wire coat, and an inner liner.

  According to another preferred embodiment of the present invention, a tire manufactured using the rubber composition for a tire tread can be provided.

  The tire is manufactured from the rubber composition for a tire tread, and exhibits improved wear resistance, life characteristics and cut chip performance as well as excellent fuel efficiency, and improved appearance characteristics.

  As the method for producing the tire, any method can be used as long as it is a method generally used for producing a tire except that the rubber composition for a tire tread is used. Detailed description will be omitted. However, the tire may include a tire tread produced using the tire tread rubber composition.

  The tire may be a passenger car tire, a racing tire, an airplane tire, an agricultural machine tire, an off-the-load tire, a truck tire, or a bus tire. The tire may be a radial tire or a bias tire, and is preferably a radial tire.

  Hereinafter, the rubber composition for a tire tread of the present invention and a tire including the same will be described in detail with reference to specific examples so that those having ordinary knowledge in the technical field to which the present invention can easily carry out. . However, the present invention can be embodied in various different forms, and the following embodiments are merely examples for explaining the present invention in more detail, and the technical idea of the present invention is limited by the following embodiments. It is not something.

Examples 1-5 and Comparative Examples 1-5

  The rubber compositions of Examples and Comparative Examples 1 to 5 were mixed in the configurations and contents disclosed in Table 1 below, and blended with a Banbury mixer to produce a rubber composition for a tire tread.

  1) Natural rubber: natural rubber, whose chemical name is polyisoprene

  2) S-SBR: solution-polymerized styrene-butadiene rubber (SBR) having a styrene content of 35%, a vinyl content in butadiene of 25%, and a Tg of -35 ° C, including 37.5 parts by weight of SRAE Oil

  3) BR: butadiene rubber produced with neodymium catalyst

4) Carbon black: carbon black having a nitrogen adsorption value of 140 m ² / g and a CTAB value of 130 m ² / g

5) Silica: Highly dispersible silica having a nitrogen adsorption value of 175 m ² / g and a CTAB value of 160 m ² / g

  6) Synthetic oil: PAH (PolyCyclic Aromatic Hydrocarbon) total content is 3 wt% or less, kinematic viscosity is 95 SUS (210 ° F SUS), aromatic component in softener is 20 wt%, naphthenic component is Synthetic oil with 30% by weight and 40% by weight of paraffinic components

  7) Natural oil 1: natural oil with a ratio of oleic acid to linoleic acid of less than 0.5

  8) Natural oil 2: natural oil with a ratio of oleic acid to linoleic acid of 0.9

  9) Natural oil 3: natural oil with a ratio of oleic acid to linoleic acid of 1.6

  10) Natural oil 4: Natural oil with oleic acid ratio of 3 to linoleic acid

  11) Natural oil 5: natural oil in which the ratio of oleic acid to linoleic acid exceeds 5.

Test example: Physical property measurement

  Rubber specimens were produced using the tire tread rubber compositions produced in the examples and comparative examples, and the Mooney viscosity, hardness, 300% modulus, viscoelasticity, etc. of the obtained specimens according to ASTM related regulations. The results are shown in Table 2 below.

  1) Mooney viscosity (ML1 + 4 (125 ° C.)): Using Mooney MV2000 (Alpha Technology) equipment, large rotor, preheating 1 minute, rotor operating time 4 minutes, temperature 125 ° C., to ASTM standard D1646 Measured in conformity. Mooney viscosity is a value indicating the viscosity of unvulcanized rubber. The higher the Mooney viscosity value, the greater the viscosity of the rubber, which may be disadvantageous in workability. The lower the Mooney viscosity value, the more workability Excellent.

  2) Hardness: Measured by DIN 53505 using a Shore A hardness meter. The higher the hardness value, the better the adjustment stability.

  3) 300% modulus: 300% modulus is the tensile strength at 300% elongation, measured according to the ISO 37 standard, and the higher the value, the better the strength.

  4) Breaking energy: It means the energy when rubber breaks in accordance with ISO 37 standard, and the strain energy until the test piece is cut with a tensile tester was measured by a numerical method. The higher the breaking energy, the better the wear performance.

  5) Viscoelasticity: For the viscoelasticity, G ′, G ″ and tan δ were measured from −60 ° C. to 70 ° C. under 10 Hz Frequency with 0.5% deformation using an ARES side instrument. Tg and −40 ° C. G indicates a braking characteristic on an icy and snowy road surface, and the lower the value, the better.

  0 ° C. tan δ indicates a braking characteristic on a dry road surface or a wet road surface, and the higher the value, the better the braking performance. 60 ° C. tan δ is a scale indicating the rotational resistance at 60 ° C., The lower the value, the better the fuel efficiency.

  As shown in Table 2, Examples 1 to 3 including natural oils 2, 3 and 4 in which the ratio of oleic acid to linoleic acid is in the range of 0.5 to 5 are comparative examples including synthetic oil. Compared with Comparative Example 2 in which the ratio of oleic acid to 1 or linoleic acid was less than 0.5, excellent values were obtained in terms of workability, wear performance, and braking performance on snowy and snowy road surfaces.

  Moreover, Examples 1-3 can confirm that it is excellent in abrasion performance, the braking performance on a dry road surface or a wet road surface, and a low fuel consumption characteristic compared with the comparative example 3 in which the ratio of oleic acid with respect to linoleic acid exceeds 5. It was.

  And when Example 2, 4 and 5 were compared, it has confirmed that workability, wear performance, and braking performance improved further as the content of natural oil increased.

  Then, a tread is made using the rubber of the comparative example and the example, and a tire of 215 / 60R16V standard including the tread rubber as a semi-finished product is manufactured. Table 3 shows the relative ratio to the braking distance, the performance on the snowy and snowy road surface, and the result of actual vehicle wear.

  The numerical value of the relative ratio has a large influence on improvement and reduction when it has a change width of 5% or more. That is, when it is 95 or less, the performance is insufficient and it is difficult to apply. If so, the performance improvement effect is a considerable level.

  As described above, in the case of an embodiment using natural oil instead of existing synthetic oil, it is possible to improve the compatibility of rubber and minimize the decrease in rotational resistance and braking performance on a wet road surface, while on an icy and snowy road surface. The result that the improvement effect of the braking performance and the wear performance was obtained.

  However, depending on the characteristic ratio of natural oil (the ratio of oleic acid to linoleic acid), if it is less than 0.5, the tradeoff between braking performance and rotational resistance on wet roads is large, and if it is greater than 5, Although the trade-off was slight, it was confirmed that the effects of braking performance and wear resistance performance on icy and snowy road surfaces were also slight. And such an effect showed the tendency which became so large that it increased within the suitable weight part.

Claims (10)

100 parts by weight of raw rubber,
70 to 120 parts by weight of reinforcing filler,
A rubber composition for a tire tread, comprising 10 to 60 parts by weight of a natural oil having a linoleic acid: oleic acid ratio of 1: 0.5 to 1: 5.   The rubber composition for a tire tread according to claim 1, wherein the raw rubber includes 5 to 10 parts by weight of natural rubber, 40 to 70 parts by weight of solution-polymerized styrene-butadiene rubber, and 20 to 50 parts by weight of neodymium butadiene rubber.   The solution-polymerized styrene-butadiene rubber has a styrene content of 20 to 50% by weight, a vinyl content of 10 to 40% by weight, a Tg of -50 to -20 ° C, and 20 to 40 parts by weight of SRAE oil. The rubber composition for a tire tread according to claim 2.   The rubber composition for a tire tread according to claim 2, wherein the neodymium butadiene rubber has a cis-1,4-butadiene content of 95% by weight or more and a Tg of -100 to -120 ° C.   The rubber composition for a tire tread according to claim 1, wherein the reinforcing filler includes 65 to 100 parts by weight of highly dispersible silica and 5 to 20 parts by weight of carbon black. The high-dispersibility silica has a nitrogen adsorption value of 160 to 180 m ² / g, a CTAB adsorption value of 150 to 170 m ² / g, and a DBP oil absorption of 180 to 200 cc / 100 g. Rubber composition for tire treads.   The natural oil is linoleic acid and oleic acid from any one natural oil selected from the group consisting of soybean oil, sunflower oil, cottonseed oil, corn oil, canola oil, palm oil, grape seed oil, and mixtures thereof. The rubber composition for a tire tread according to claim 1, comprising a mixture obtained after extraction, separation, and mixing.   The rubber composition for a tire tread according to claim 1, wherein the natural oil has a content of unsaturated fatty acids including the linoleic acid and oleic acid of 60 to 90% by weight.   The tire tread rubber composition is any one selected from the group consisting of bis- (trialkoxysilylpropyl) polysulfide (TESPD), bis-3-triethoxysilylpropyl tetrasulfide (TESPT), and mixtures thereof. The rubber composition for a tire tread according to claim 1, further comprising 5 to 20 parts by weight of one silane coupling agent with respect to 100 parts by weight of the raw rubber.   A tire manufactured using the rubber composition for a tire tread according to claim 1.